MICROVENA ANGEL WINGS ATRIAL SEPTAL DEFECT DEVICE CLINICALS
This article was originally published in The Gray Sheet
MICROVENA ANGEL WINGS ATRIAL SEPTAL DEFECT DEVICE CLINICALS should begin in six to eight weeks pending approval of an investigational device exemption application, according to Rudy Mazzocchi, president and CEO of the privately held company. Speaking at the Dain Bosworth healthcare seminar in Minneapolis on Sept. 13, Mazzocchi said the nonsurgical device utilizes the "shape-holding" properties of nitinol, a nickel-titanium alloy, to repair holes in the septal wall of the heart. Developed in collaboration with the University of Minnesota, the device consists of two small nitinol "frames," which are each covered with a polyester fabric and are attached together with a central "button." The device is delivered to the septal wall via a special catheter. Prior to deployment, the frames are folded up inside the catheter; they regain their shape after they are placed on the septal wall. The device is positioned by advancing one of the two attached frames through the end of the catheter on one side of the defect, after which "with slight tension applied, the second frame is deployed on the other side, thereby sandwiching the defect," Mazzocchi explained. Once in place, clots immediately begin to form on the device and completely cover it within six to eight weeks. The device could be used to treat atrial and ventricular septal defects as well as patent foramen ovale (PFO), a defect that allows blood clots to pass into arteries and cause strokes, Mazzocchi said. After receiving the IDE for U.S. clinical trials, Microvena plans to initiate training programs for trials of the device in Europe and India. Other companies working on catheter-delivered septal defect repair devices include Bard. The firm currently is redesigning its stainless steel and dacron Clamshell Septal Umbrella after encountering difficulties in clinicals related to the failure of struts used to hold the device in place ("The Gray Sheet" Dec. 2, 1991, p. 4). Also under development by White Bear Lake, Minnesota-based Microvena is its Clot Buster mechanical thrombectomy device designed to macerate blood clots in peripheral vessels. The device, which recently entered Phase II clinical trials, uses air pressure to drive a disposable rotor at 150,000 rpm. The distal rotor runs for about two minutes and creates a vortex at high speeds that draws clots into it. Clots are then broken down and expelled through side ports in the device. Mazzocchi reported that in a 10-patient Phase I trial of the device, 85-100% of clots were effectively macerated. Surgical and drug therapies for thrombus average 45-80%, according to the exec. Prototypes are also being evaluated for other applications including venous thrombectomy for pulmonary embolism, cerebral thrombectomy for acute strokes and coronary thrombectomy. Founded in 1989 as a joint venture between Mazzocchi and Phillips Plastics, Microvena currently operates independently of Phillips, which retains a majority equity interest. Microvena focuses on the interventional catheter market in four areas -- pediatrics, cardiology, radiology and neuroradiology -- and anticipates sales of $7-8 mil. this year. The company markets its products through nine direct sales reps in the U.S. and 23 international distributors. Current product offerings include the firm's Ultra Select nitinol guidewires, which are marketed in North America by Medtronic for use in coronary angioplasty and by Medtronic for other uses including general radiology, pediatrics and neuroradiology. The distal ends of the wires have gold plated tungsten coils for easier visualization under fluoroscopy. Mazzocchi indicated that the longer and softer versions of the guidewires have proven effect in tortuous vessels of the brain and can access anomalies and diseases in the brain including vascular tumors, hemorrhages, aneurysms and vascular defects. The firm also sells microcatheters that can be used for predilatation and in drug treatment for coronary thrombolysis. In addition, three varieties of microcatheters are offered for cerebral applications, including therapeutic treatment of diseases and anomalies of the brain. The microcatheter line also includes devices that can be used for certain pediatric diagnostic applications and for treatment of peripheral embolization in the kidney or liver. Other products marketed by Microvena include "microsnares," approved for peripheral use in a variety of sizes. Advanced through the firm's microcatheters, the angled metal loops can be used to ensnare "foreign objects" in blood vessels, eliminating the need for "surgical retrieval of broken fragments" of medical devices as well as bone fragments resulting from head trauma. The devices, available in 2 and 4 mm sizes, also can be used to manipulate vascular stents, as well as coils and detachable lobes used in the treatment of vascule aneurysms. Five larger snares offered are sized from 5 to 35 mm. The larger sized snares are referred to as "interventional hands," Mazzocchi explained, and can be used for repositioning vena cava filters and stents, and to pull other catheters and wires along a tortuous path. Also marketed by the firm are the Solostick dilator needles, which combine a "single wall" puncture needle with a vessel, dilator, Mazzocchi said. Guidewires, microcatheters and microsnares that can be used in the brain represent the firm's entry into the burgeoning cerebrovascular marketplace. The interventional neuroradiology field is expected to grow from a current $35 mil. to over $200 mil. by the year 2000, Mazzocchi said. The exec added "we're moving to be right on Target," a reference to a leader in the field, Target Therapeutics. Microvena development projects in this area include a nitinol occlusion device for use in embolization. "Preliminary results with these devices have proven them to be advantageous over micro-coils and detachable lobes for the purpose of embolization," Mazzocchi said.
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